# Video
# Tree-sitter
# STOOOOOOOOOOOOOOOOOOOOOP
If you're thinking:
> "wOw nOw i'lL kNoW EvErYtHiNg aBoUt lSp tOo" <!-- stop -->
**NO!**
# Tree-sitter Is NOT
- Language Server Protocol (LSP) <!-- stop -->
- A Compiler <!-- stop -->
- An Interpreter
# Tree-sitter Is
- Parser generator tool <!-- stop -->
- Incremental parsing library <!-- stop -->
- A query engine (more on this later)
# Tree-sitter Is
A "framework" to:
- Generate a syntax tree
- Ask questions about the tree
# Why Tree-sitter (In An Editor)
- Editors that use tree-sitter:
- Neovim (BTW)
- Helix
- Zed
- Emacs
- (Maybe more?)
# Why Tree-sitter (In An Editor)
- Incremental
- Error Recovery
<!-- Also very important. Not just because you mostly write broken code,
but as you're writing the code is mostly broken.
It's only not broken when you're finished writing. -->
- Queries
# How Does Tree-sitter Work?
# Underlying Stack: `grammar.js`
- Grammars are written in "javascript" <!-- stop -->
- You write them in javascript, but more correctly "A Javascript-like DSL".
- `grammar.js` <!-- stop -->
- These are compiled to `parser.c` via the tree-sitter cli
# Underlying Stack: Results of `grammar.js`
```
├── src
│ ├── grammar.json
│ ├── node-types.json
│ ├── parser.c
│ ├── scanner.c
│ └── tree_sitter
│ └── parser.h
```
# Why C (since it's outdated & illegal)?
- Only dependencies is a C Compiler
- Good FFI story for lots of languages
This results in tree-sitter being very portable
# Then what?
Compile the C code to a shared library!
```
$ cc -o ./build/parser.so -I./src src/parser.c src/scanner.c -shared -Os -fPIC
```
# After compiling, then what?
Now you have:
```
$ ls -al build
total 304
drwxrwxr-x tjdevries 4096 ./
drwxrwxr-x tjdevries 4096 ../
-rwxrwxr-x tjdevries 299680 parser.so*
```
# Shared Library
You can load that shared library as a parser inside of some application
that supports tree-sitter.
In this case, we'll use Neovim to explore and show some of what tree-sitter is doing.
# Exploring Tree-sitter
*NOTE*: Some of you may be triggered. I'm about to show you `lisp` code.
- Consider this your final warning <!-- stop -->
- Also, `scheme` is cool :)
# Exploring Tree-sitter
> Open `example.go` file
# What is Tree-sitter Used For (In An Editor)?
- Highlighting
- Embedding Languages
- Indenting <!-- stop -->
- Structural Editing
- Text Objects (`daf` -> `d`elete `a`round `f`unction)
- Selection
- Move <!-- stop -->
- Code Context <!-- stop -->
- Folding <!-- stop -->
- ...
# What is Tree-sitter Used For (Outside Editors)?
- Code Analysis
- Code Linter
- Code Highlighting
# Conclusion